Gimbaled,vehicle-mounted post-hole digging system



J. D. SMITH July 1, 1969 GIMBALED, VEHICLE-MOUNTED POST-HOLE DIGGING SYSTEM Filed Jung so. 1967 Sheet 5T wi INVENTOR. JOHN D. SMITH ATTORNEYS J. D. SMITH July 1, 1969 GIMBALED, VEHICLE-MOUNTED POST-HOLE DIGGING SYSTEM Sheet Filed June 30, 1967 INVENTOR. JOHN D. SMITH ATTORNEYS United States Patent 3,452,829 GIMBALED, VEHICLE-MOUNTED POST-HOLE DIGGING SYSTEM John D. Smith, Scottsdale, Ariz., assignor of one-half to Martensen Enterprises Inc. Filed June 30, 1967, Ser. No. 650,380 Int. Cl. E21c 11/02, /08, 9/00 US. Cl. 173-28 4 Claims ABSTRACT OF THE DISCLOSURE The present invention pertains to posthole digging apparatus, and more specifically, to portable posthole digging apparatus wherein the apparatus is vehicle-mounted.

A variety of prior art apparatus has been proposed and is presently being used for digging postholes in terrain that is less than ideal. In circumstances where the holes are being dug in hilly or uneven locations, it has generally been the practice to carefully position the vehicle upon which the digging apparatus is mounted to insure the vertical direction of the posthole. To facilitate this positioning, and to expedite the drilling, complicated apparatus has been proposed wherein the auger shaft may be tilted or pivoted about an axis to compensate for the sloping of the ground upon which the vehicle rests. If, however, the ground slopes not only toward or away from the proposed posthole but also in such a way to tilt the vehicle about its longitudinal axis, great pains must be taken to compensate for the slope to insure that the posthole is vertical.

The prior art has also recognized the advantages of portability and in combining a posthole digging apparatus with a vehicle; however, the prior art has failed to recognize the advantages to be gained by permitting the vehicle to be a public road highway vehicle with a single operator while permitting the same operator to operate the posthole apparatus when the digging site is reached. It has been the practice in the prior art to completely divorce the operation of the vehicle from the operation of the digging apparatus such that the vehicle must very accurately be positioned prior to the actual digging operation in order that the operator may assume control of the digging apparatus. If, after the digging apparatus has been manned by the operator it is desired to make minute adjustments in the positioning of the vehicle, it is necessary for'the operator to leave the controls of the digging apparatus and return to the controls of the vehicle in order to reposition the latter and then return again to the controls of the digging apparatus.

It is therefore an object of the present invention to provide a posthole digging system wherein the posthole digging apparatus is vehicle-mounted and may be controlled to provide a vertical posthole without regard to the slope or inclination of the ground upon which the vehicle rests.

It is another object of the present invention to provide a posthole digging system wherein digging apparatus is vehicle-mounted and wherein the vertical alignment of the posthole is insured through a gimbal support for an auger shaft forming a part of the digging apparatus.

It is still another object of the present invention to provide a posthole digging system wherein the operator of the vehicle upon which the apparatus is mounted may continue to operate the vehicle even though he has assumed a new position primarily intended for the control of the digging apparatus rather than the control of the vehicle.

It is still another object of the present invention to provide a posthole digging system wherein the vehicle may be controlled from either of two positions, one of which is primarily intended for controlling the vehicle during public highway travel and the other of which is intended primarily for utilization immediately prior to digging a posthole for insuring the proper positioning of the vehicle for the digging operation.

These and other advantages of the present invention will become apparent to those skilled in the art as the description thereof proceeds.

Briefly, in accordance with the embodiment chosen for illustration, the present invention contemplates the utilization of a four-wheel-drive type vehicle having a frame mounted at the rear portion thereof for supporting a posthole digging apparatus. Typically, the power take-off apparatus of the vehicle may be utilized for driving the auger of the posthole digging apparatus. The drivers seat is positioned in the normal fashion; however, a digging apparatus operators seat is positioned adjacent to the drivers seat in the reverse direction to facilitate observing the posthole digging apparatus during operation. Duplicate controls are provided to the rearward-facing seat to enable the operator to position the vehicle and drive the vehicle for limited distances to facilitate the positioning of the digging apparatus. The digging apparatus is provided with a vertically movable auger shaft to which an auger may be attached; the shaft is supported in a gimbal arrangement to permit the shaft to be pivoted about two perpendicular axes, the inclination about which is controled by a plurality of hydraulic piston and cylinder combinations. The vertical travel of the auger shaft is also controlled by a piston and cylinder arrangement and the power for rotation of the auger shaft is provided through the power take-off mechanism of the vehicle connected through universal joints to the gimbal-mounted power transmission.

The present invention may more readily be described by reference to the accompanying drawings, in which:

FIGURE 1 is a perspective view of a posthole digging system constructed in accordance with the teachings of the present invention.

FIGURE 2 is an enlarged view of a portion of FIG- URE 1 showing the accelerator linkage to provide dual control of engine speed.

FIGURE 3 is a perspective view of a posthole digging system constructed in accordance with the teachings of the present invention showing the apparatus secured for highway travel.

FIGURE 4 is a view of a portion of the systems of FIGURES 1 and 3 showing the relationship of the rearward-facing seat, the hydraulic controls for the digging apparatus, and a portion of the dual controls for operation of the vehicle.

Referring now to the drawings, a four-wheel-drive type of vehicle 10 is provided with a frame 11 mounted thereon extending rearwardly thereof for mounting digging apparatus. A drivers seat 15 is provided in the normal position to enable the vehicle to be driven on public roads; further, an operators seat 16 is mounted on the vehicle and is positioned adjacent to and directed oppositely to the seat 15. The operators seat 16 is positioned to enable the occupant thereof to control the posthole digging apparatus. In addition to controlling the posthole digging apparatus from the seat 16, the operator may also drive the vehicle through duplicate controls provided therefor such as shown in FIGURE 2 wherein the vehicle accelerator may be operated either by direct pressure on the pedal 25 or by pressure on an auxiliary accelerator 26 which effectively operates the pedal 25 through the shaft 27 pivoted in a journal plate 28 and through a shaft 29. The vehicle clutch pedal 30 operates a hydraulic slave cylinder (not shown) in the conventional automotive manner; the duplicate clutch 31 provided for the occupant of the seat 16 merely hydraulically operates the same slave cylinder to effectuate clutch disengagement and engagement. In addition to the usual gearshift which is provided with the vehicle 10 and which is thought unnecessary to illustrate in the accompanying drawings, a lever 33 is provided for disengaging the transfer case and a second lever 34 is provided for engaging the power take-off to permit the vehicle engine to drive the posthole digging apparatus. Power from the power take-off of the vehicle is transmitted through a plurality of V-belts 38 to V-belt pulleys or sheaves 39 and subsequently to a shaft 40 journalled in a pillow box 41. The rotation of the shaft 40 is transmitted through a U-joint 43 to a power shaft 44 slidably coupled to a second power shaft 45 which, in turn, is connected to a pivotally mounted transmission 48.

An auger shaft is slidably supported in the transmission 48 and is connected at its upper end to the piston shaft 51 of the cylinder and piston arrangement 52. The cylinder 52 is connected to a frame 53 which, in turn, is secured to the transmission 48. Thus, the auger shaft 50 is free to extend upwardly and downwardly in accordance with the positioning of the piston 51 while nevertheless being rotated by the transmission 48 which, in turn, receives power from the shaft 45. The transmission 48 is mounted for rotation about an axis 57 by mounting the transmission 48 by stub shafts 58 journaled in a gimbal frame 60. The gimbal frame 60 is pivotally secured to the frame 11 through stub shafts 62 journalled to the frame 11 to thus permit the frame 60 to pivot about the axis 65.

Pivoting of the auger shaft 50 about the axis 65 is accomplished by extending or retracting the hydraulic piston and cylinders 68 and 69 which are attached at one end thereof to the frame 11 and at the other ends thereof to extensions 71 and 72, respectively, attached to the gimbal frame 60. Pivoting of the auger shaft 50 about the axis 57 is accomplished by the extension or retraction of the hydraulic piston and cylinder combination connected at one end thereof to the frame 53 and at the other end thereof to an extension 84 connected to the gimbal frame 60. The extension or contraction of the hydraulic piston and cylinder combinations 68, 69 and 80 is accomplished through the utilization of hydraulic control valves 87, 88 and 90. Each of these valves is connected to a source of high-pressure hydraulic fluid (not shownsupplied by a hydraulic pump which may be operated either from the vehicle power take-off or by the vehicle battery) and connects to one of the hydraulic cylinders. Movement of the valve handle in one direction applies high-pressure hydraulic fluid to the cylinder, causing the extension of the cylinder-piston combination. Movement of the control handle of the valve in the opposite direction applies hydraulic fluid under pressure to the opposite side of the piston within the hydraulic cylinder to cause the pistoncylinder combination to contract. The utilization of hydraulic controls for the contraction and extension of piston-cylinder combinations is well known in the art and it is felt unnecessary to explain the operation of such devices here; further, the utilization of control valves for extending or contracting the piston-cylinder combinations is also well known in the art and need not be described in detail.

The operation of the system of the present invention may now be described. The posthole digging apparatus may be collapsed and carried on the vehicle as illustrated in FIGURE 3 on a public highway at normal highway speeds. When the digging site is reached, the operator leaves the drivers seat 15 and places himself in the operators seat 16. The auger shaft 50 is elevated to an approximately correct position by manipulation of the hydraulic valves 87, 88 and 90. The operator, sitting in the seat 16, may easily reach the gearshifting lever of the vehicle 10 and may place the vehicle in whatever gear he deems appropriate and may cause the vehicle to move in any direction desired by manipulation of the auxiliary accelerator and clutch .pedals while guiding the vehicle with his hand on the vehicle steering wheel. The vehicle may then be secured in position by pulling the hydraulic brake lever 90 in the direction indicated by the arrow 91 and locking it in position. With the vehicle thus secured in position, the operator may then manipulate the hydraulic controls until the auger shaft 50 is in a precisely vertical position. By manipulation of the levers 33 and 34 together with the manipulation of the auxiliary clutch pedal 31, the transfer case may be disengaged and the power take-off may be engaged. The V-belts 38 thus begin driving the shaft 44 and the transmission 48. (It will be obvious to those skilled in the art that an additional U'joint will have to be placed between the shaft 45 and the transmission 48 to accommodate pivotal movement of the transmission 48 on the gimbal axes.) The auger shaft may then be forced to descend by actuation of the hydraulic control lever 90, causing the shaft 50 to descend thus forcing the auger 95 into the ground. The speed of the auger shaft is controlled by the auxiliary accelerator pedal 26 and the descent of the auger 95 into the ground may be accelerated by the pressure applied on the auger through the auger shaft from the piston 51 receiving thrust from the hydraulic pressure applied thereto from the control valve 90.

It may be seen by those skilled in the art that the posthole digging system of the present invention provides a completely portable posthole digging apparatus wherein the operator may position the vehicle from the apparatuscontrolling seat rather than having to accurately position the vehicle prior to manipulating the controls of the apparatus; further, the auger of the present system may accurately be positioned vertically without regard to the inclination of the ground upon which the vehicle stands. For example, if the posthole is to be placed on the sloping berm of a highway, it would, under ideal circumstances, only be necessary to back the vehicle perpendicular to the axis of the road and then orient the auger vertically by actuating the piston and cylinder 68 and 69. However, if the axial line of the highway is also sloping (e.g., a hill), then positioning the vehicle so that the auger can be oriented vertically by merely pivoting it about a single axis becomes an almost impossible task; accordingly, the vehicle of the present invention may be positioned in any convenient manner and, through the gimbaling provided therewith, the present system provides for the vertical orientation of the auger without regard to the inclination of the vehicle.

It will also be apparent to those skilled in the art that many modifications may be made in the present system without departing from the spirit and scope thereof; accordingly, it is intended that the present invention be limited only by the scope of the claims appended hereto.

I claim:

1. A posthole digging system comprising: a vehicle having drivers controls including a steering wheel and a lever for selectively engaging and disengaging a transfer case; a drivers seat mounted on said vehicle to permit operation of said drivers controls; a frame mounted on said vehicle to support digging apparatus; an operators seat mounted adjacent to and facing reverse of the drivers seat to permit operation of said digging apparatus and positioned to permit an operator to manipulate said steering Wheel and said lever for engaging and disengaging the transfer case; duplicate drivers controls for all said drivers controls excepting said steering wheel and said lever for selectively engaging and disengaging the transfer case, said duplicate drivers controls being connected to said drivers controls and positioned for operation from said operators seat; digging apparatus supported by said frame including: an auger shaft pivotally supported on said frame; means controllable .by an operator in said operators seat for pivoting said auger shaft; and power means coupled to said auger shaft for rotating said shaft.

2. The combination of claim 1 wherein said digging apparatus comprises: a two-axis gimbal support pivotally mounted on said frame for pivotal movement about one of said axes; power transmission means pivotally supported by said gimbal for pivotal movement about the other of said axes; and an auger shaft slidably supported in said power transmission means.

3. The combination set forth in claim 2 wherein said auger shaft is connected to a hydraulically actuated piston and is axially movable therewith.

4. The combination set forth in claim 2 wherein said References Cited UNITED STATES PATENTS 2,529,192 11/1950 Rossner l-77 2,856,155 10/1958 Putt -17343 X FOREIGN PATENTS 137,756 9/ 1948 Australia.

ERNEST R. PURSER, Primary Examiner.

US. Cl. X.R. 173-43; 77 1 

